This invention relates to a vacuum pumping stand for the cyclic pumping-down of a container and for maintaining an operating vacuum in the container. More specifically, this invention relates to a vacuum pumping stand for the cyclic pumping-down of a container and for maintaining an operating vacuum in the container, which has a first and a second vacuum pump which are arranged in series and form a first and a second pumping stage.
In the art, pumping stands of the above-mentioned type are used, for example, for the cyclic pumping-down of adsorbers in order to carry out the regeneration of zeolites or other adsorption agents in a vacuum in the case of vacuum swing systems or pressure-vacuum swing systems for oxygen and nitrogen enrichment. In the case of such systems, it is important that large amounts of gas are sucked relatively rapidly out of an adsorber and subsequently an operating vacuum is maintained in it. Currently, this takes place in pumping stands which are constructed of rotary compressors operating in several stages. Although such pumping stands are satisfactory with respect to their function, technical experts are trying to further reduce their energy requirement because this energy requirement plays an important role in cyclic processes. However, recently only little progress has been made with respect to a reduction of the energy requirement in the case of pumping stands constructed of rotary compressors.